Boring tool



March 20, 1945. v 5, 5mm 2,372,027

I BORING TOOL Filed Dec. 3, 1943 He. 1. FIG. 2.

INVENTOR ATTORN S.

Patented Mar. 20, 1945 11 Victor E; Sni'itli,;Detrcit,-Mich., assignor to v a -M ildred E. Smith,'l )etroit, Mich;

Application Decemlic 11,9743:v S t N- 51282-51 i r mm. (or. 77-58) The present invention relates: to boring tools comprising a socketholder and cutter separable therefrom for purposesofreplacement or inter,-

. Theprincipal object of the invention is toprochangeability.

.yide such a combination, whichis inexpensive to manufacture, having apositive drive connection between the rotary socket holder and cutter, not

likely tobe brokeneven though subjectedgto con ;siderableshock or strain.

- A further object is to provide a bor ing tool in which the cutter is driven by the socket holder through both frictional-wedging engagement, and

by. positive keying 1 action. I V d i I Another-object is to provide such a combination :where-thecutter is particularly intendedfor counterlooringpurposes and wherea pilotis, used to guide the tool into the. work, the pilotentering a hole or socket previously formed in the work;

I Otherobiects and advantages of theinvention will appear in the following detailed description,

taken in connection with the, accompanying drawing, forming a partof this specificatiomand .in which drawing:

. Fig, 1 is a view partly'in el'evation and partly in; vertical section of a combination of socket holder and cutterconstructed according to the present invention.

Fig.2 is a cross sectional view on the 11552;: of Fig. .j i f: I ;Fig. 3 is top plan view ofthe cutter.

In the drawing A designates a socket holder including a, socket portion 3 and ashank Clor insertion in a suitablechuck or other driving means, not shown; and D a; cutter includin e head. E and a shank F for insertion into the socket portion B to form a. driving connection therewith. In the example shown, the cutter D is a counterborer including a pilot G comprising-a nut H and a pilot rod J having a head K anda stem L. The preferred details of the pilot are disclosed and claimed in my copending application for patent filed ,Dec. 3, 1943, Serial No. 512,827. a I

The drawing also shows a retainer means M adapted to prevent accidental removal ofthe cutter from the socket holder but forms no essential part of the present invention, it being disclosed and claimed in my copending application for patent filed Dec. 3, 1943, Serial No. 512,826.

The socket portion B is formed to provide a ;.a reduced minor, eccentrically located cylindrical bore 1 forming an extension of-the bore 6. These bores may be accurately formed by the use of standard tools-and require no difiicult machining;

For instance the bore 1 may be formed by drilling, ,usinga drillhaving the usual tapered leading end whichprovidesthe conicalcavity 8 shown inFigs. 1 -and..4. It is also preferred-to provide arelatively short bore 9 between the bores Band .1 of .greaterdiameterthan andcoaxial with bore 6 for l a purpose to b subsequently setforth.

, In the example shown, a transversehole I0 is ,providedthrough the walls of the socket portion adjacent the inner end of bore Lafiording a way intersecting th latter, for accommodation of any convenient cutter releasing element, such as a dr-ift-pin,;not shown, but usually used to release the shank of the cutter from thesocket- The shank F of the cutter includes a major. irusto conical portion l l which is placed in frictionalwedging relation to the wall of bore 6, and aminor, reduced eccentrically located,cylindrical portion l2 forming an xtension of the portion l I which is placed in telescopic relation in thebore ,1.. If desired the upper or free end of portion l2 .may have achamfered edge I3 to mor readily coaotwith the tapered releasing element above referred to. v 1, It is to .be noted from Figs. 1 and 3 that the cylindrical portion I2 is within the circle defining the upper or smaller end of the frusto-conical portion ll, providing a narrow shoulder or ledge l4 .whichjconfronts theupper wall [5 of bore 9. v

The cutter D, in the example shown, is provided with an-axial way 15 open to theleading edge I! of head E-and open to the free end of minor portion l2, and extending throughout the length of th -portions]! and 12, to accommodate the'stem L-of the pilot, as the head E is ground away due to wear and sharpening. This way It also facili-- tates assembling the tool and particularly placing of the nut H as set forth in my aforesaid applicasocket holder and cutter, since the ledge l4 does major relatively long, tapered, central bore 6 and not contact the wall I5, and the tapered bore 6 may be made accurate and clear of any fillet at its inner end. The overall length of the stem F is sufiicient so that its upper end partially intersects the way of hole l0 so as to encounter thetapered cutter releasing element above referred to. The primary function of the retainer M is to prevent the cutter from accidentally dropping or being shot from the holder when the cutter releasing element is given a sharp blow to break the irictional-wedging relation of the cutter stem with the wall of bore 6, but may be dispensed with.

In operation, the cutter may be primarily driven by the frictional-wedging drive connection above referred W 3 3 a PQ i V l? lwl l 31 9 1 th minor portion 1-: of the cutter stegnip the'bore I, the portion l2 being very sturdy notwithstanding the presence of the way It extending throughv it. In practice it has been found superior to the common angular tang 'found on drills, taps, counterborers and the like which aregitentwistedpfh rendering the tool useless. Furthermore the-way I6 is desirable where a pilot used, and for cool.- ing purposes, and would further weaken atom provided with an ordinary tang.

I claim: 1. ln'a boring-tool the combination of asooket holder and a cutterincluding'a cutting head and of said firstborefan'd areduced eccentrically located cylindrical portion forming-an extension of said frusto-conical portion, in telescopic relation in said third bore, and withthe smaller-end of the frusto-conical portion accommodated in, but

out ofcontact with the wall oi said second bore.

In a boring tool,the combination of a socket holder and a cutter including a cutter head and a shank detachably received in said socket holder, thesocket holder provided with a tapered central axial bore for a portion of its length, with itswider end near the open end qf-the socket, and a'red-uced cylindrical bore eccentrical'ly' locatcd with respect to and forming anextension of; the smaller Tend of; saidtapered bore, and said shank providedwith a irusto-conical portion in frictional-wedging drive cooperation with the wall of said't afpered bore and areduced eccens tricall-y locatedcylindrical portion fpmningan extensihn of said frusto-conical portion, intolescopic relation in said eccentricaliy located bore, team" a positive drive between the socket holder and the cutter;

' 3. In a counterborin g tool, the combination of a, socket holder, a counterboring tool including a -,tiona1-wedging drive cooperation with the wall of t said tapered bore, and a reduced eccentrically located cylindrical portion forming an extension of .paid irustof-conical portion in telescopic relation counterboring tool, and said counterboring tool provided with an axial way, for the stem or said pilot, said axial way open at the leading end of said head and the free endof said eccentrically located portion of the stem, and extending throughout the length of-said frusto-conical and reduced cylindrical portions of said shank to accommodate saidpilot stem, and said pilot stem extending only throughout a portion of the'length of saldaxialway, whereby heat resulting from operation of the'tool may ilnd egress to the atmosphere -through said wayand'transverse hole.

4. In a counterboring tool, the combination of a socket holder, a counterboring tool including a cutting head and a shank, and a pilot for the counterbor-ing tool including astem, said socket holder provided with a' -ma'jor central axial bore upon at its tool receiving end, a reduced minor cylindrical bore eccentrically located with respect to-and forming an extension of said major bore, and a transverse hole open to the inner end of said reduced cylindrical bore and to the outside of the socket holder, said shank provided with a major portion fitting said major bore or the holder and a reduced minor eccentrically located" cylindrical portion forming an extension of said major portion of the stem in telescopic relation 'to said minor bore of the holder, to form a positive drive between the socket holdepand counterbori-ng tool, and said counterboring tool provided with an axial way, for-thestem of said pilot, said axial way open at the leading end of said head and open to the free end of said minor porti-on of the stud, and

- extending throughout the length of said major ancl'minor portions of said shank to accommodate said pilot stem, and said pilot stem extendinconly throug-hout a portion ofthe length orsald axial way; whereby heat l-esulti ng from operationof the tool may find egress to the atmospherethroughsa'id way and transverse hole.

- E. SMITH. 

